For two of the toughest jobs in government, Christine Fullard and Elaine Webster ran a gauntlet of background checks and polygraph tests. They worried what their neighbors would say to federal agents, and answered probing questions about their sex lives. Finally, they were hired at the Central Intelligence Agency. Eight years later, Fullard and Webster still hold the security clearances required of any of the agency's intelligence analysts. And what do they do for the CIA?

They take out the trash.

The women, Fullard of Northeast D.C. and Webster of Oxon Hill, have been custodial workers at the CIA since the summer of 1973. They are two of about 75 people, mostly black women with children at home, who brave a long commute by bus and subway to toil among the elite at the agency's Langley, Va., headquarters. And to hear them tell it, things are often a touchy matter of Spy vs. Sponge.

"I've had more doors slammed in my face than I want to think about," said Webster, 32, a big, jovial woman, as she sat the other day in her aqua-blue uniform in a small office at the agency's main building. "Whenever we're around, they're always shouting, 'Here come the cleaning ladies' or 'Here come the garbage ladies.' That really burns me up."

"Some of the people here," added the slighter, quieter Fullard, also 32, "are very snobbish."

"Sometimes they'll be taking paper clips out of their desks and shooting 'em across the room," Webster put in. "Yeah, paper clips," Fullard agreed with a giggle. "And popcorn, and peanuts, and sometimes they'll even be throwing spitballs."

Between them, Fullard and Webster hold perhaps the government's least desirable posts. Security demands also make the job one of the hardest for which to be hired. For vacuuming carpets, scrubbing restrooms and removing trash, the women earn $5.26 an hour. And the mission they have chosen to accept is frequently punctuated by odd encounters with edgy agents. "These people are so wrapped up in their work," Webster said, heaving a sigh. "It's like they are all in another world."

What with the CIA's extraordinary working conditions, its out-of-the-way location, plus daunting background checks and lie-detector tests that most prospects fail, the cleaning crews at the agency are perennially short-staffed.

The polygraph examination is especially intimidating, employes said. Former CIA mail truck driver Elizabeth Taylor, a 44-year-old mother of two and staunch churchgoer from Northwest D.C., recalled that she was "angry for a month" after the well-dressed man running the polygraph machine probed her about her sexual habits. "I just never dreamed I would be asked anything like that," she said. People familiar with the test said several questions deal with homosexual activity -- a factor, CIA spokesman Dale Peterson said, "that could make somebody vulnerable to the blandishments of foreign powers."

The General Services Administration, which maintains the mammoth, 1 million square-foot complex tucked in the Northern Virginia woods, says it must hire at least 35 new custodial workers to bring the force to its full strength of 111.

GSA officials aren't too hopeful of success. In the meantime, the agency, which is supposed to get what GSA calls "executive level cleaning," must make do with the no-frills package: light dusting, window-washing once a year, and a thorough vacuuming of most offices every other week.

"For as long as I can remember, and I go back to 1960, it's always been tough to send people over there," said Ted Leininger of the GSA's Public Building Service. "For one thing, it's out in the middle of the boonies. And then there's that difficult security clearance."

Ed Kansler, GSA's acting chief of building management for the National Capital Region, said the CIA routinely approves about 15 percent of those who apply for custodial duty, usually after a background check of at least six months. Peterson said "that figure seems way too low," and disputed the six-month figure as "way too long," but others said the actual figures are even lower and longer.

"We just had 30 people apply here and only three made it through security," said a woman in the Public Building Service's CIA field office. The woman, who asked not to be named, said her own clearance, just recently awarded, took nine months to arrive. "It was something else, let me tell you," she said of the long wait.

Peterson said such precautions are necessary, even though custodial workers don't see classified material. "Security is paramount," he said, adding that even if the floors are filthy, a condition he says doesn't exist, "security is our absolute priority."

Fullard and Webster, meanwhile, have plenty to allow about cleaning.

In an interview, during which the women warned that the room might be bugged, Webster told of tangling with security-conscious staffers who stand in the way of her vacuum. "If they're not behind you," she said, "then they're in front of you, following you foot for foot and heel for heel. You can't hardly move. When you ring the buzzer to be let into an office, someone always says, 'Let me get someone to escort you,' or 'Let me get someone to watch you,' or 'Let me get someone to follow you.' That's really the words they use."

Webster said that less than a year ago, she was going about her rounds "pulling the trash," when she entered an office on the building's fourth floor. "There were two secretaries sitting up front and I asked them, 'May I have the trash?' They said 'yes,' so I just took for granted that I could collect the trash. But as I started doing it, a man came from nowhere, and started pushing me away and screaming at me, 'Get, get out of here, don't you ever come in here like this!' Oh, I tell you, the spit was flying. I wanted to push him back, and there were a couple of words I wanted to say to him, but instead I went right to my supervisor."

Webster said she and her GSA supervisor decided to boycott the office for a week, refusing to clean it or empty the trash "until we received an apology from the gentleman." When a written apology arrived, Webster said cleaning resumed. "A couple of the CIA people told me not to be upset, but that this man was so involved in his work, this is the way he got from time to time."

Fullard, meanwhile, told of an incident a few years ago in which a CIA employe tossed a burn bag filled with classified documents into a trash can by mistake. "It was really a trip," she said. "They took about 200 trash bags and piled them outside the building, and these men in rubber suits went through all of them until they found what they were looking for."

Dale Peterson said the agency is clean enough. But outside the main building the other day, the CIA's statue of Nathan Hale had a decorative cobweb fringe.